Dyeing of textiles for use in garments, rugs, tapestries and the dyeing of other fibrous materials such as hair and the like has been in existence for ages. One of the most popular classes of dyes for such use has been sulfur dyes. Sulfur dyes have been and are relatively inexpensive as compared to other classes of dyes. However, in the recent years, the cost advantages of sulfur dyes has diminished such that there is no longer a large competitive edge for using sulfur dyes as compared to other classes of dyes. As a result of this diminishing of the cost advantages of sulfur dyes, the disadvantages of sulfur dyes has become more of a factor in the selection of dyes for such uses.
One of the most noticeable disadvantages associated with sulfur dyes, especially black and brown sulfur dyes, is the susceptibility of sulfur dyes to become over-oxidized by bleaching agents, such as chlorine bleaches, oxygen bleaching agents, activated oxygen bleaches and UV radiation, such as from the sun, and the like. When a sulfur dyed textile is exposed to bleaching agents, the sulfur dye has a propensity to react with the bleaching agents to be over-oxidized. As a result of the over-oxidizing of the sulfur dye, the sulfur dyed textile and/or other fibrous material begins to exhibit dye damage leading to color change.
Another problem associated with conventional sulfur dyes and textiles dyed by the conventional sulfur dyes is the problem of aging or tendering. Aging of the textiles results in large part from the fiber damage caused by sulfuric acid produced during storage and transportation of the conventional sulfur dyed textiles.
Yet another problem associated with conventional sulfur dyes and textiles dyes by the conventional sulfur dyes is the problem of the poor wash fastness.
Accordingly, there is a need to develop sulfur dye protection systems that protect sulfur dyes, especially sulfur dyes on textiles and/or other fibrous materials, from oxidation by oxidizing agents, such as bleaching agents, from tendering/aging and from reducing-color fastness environments, such as laundry wash liquor, especially bleach-containing laundry wash liquor, compositions comprising such systems, and methods for using such systems, and a need to increase the bleach stability of sulfur dyes, such as by modifying existing sulfur dyes and/or “building-into” newly formed sulfur dyes increased bleach stability properties; to dye textiles with such sulfur dyes, especially bleach stable sulfur dyes, and/or make bleach stable sulfur dyed textiles.